Nettle caterpillars such as Darna pallivitta, Darna trima and Darna bradleyi are major pests that attack palms in Southeast Asia and Hawaii. They feed on leaves of palms and eventually kill the trees, leading to a decreased crop. Therefore, biological pest controls have been attracting great interest, promising one of which is the use of a sex pheromone (Non-Patent Literature 1).
Sex pheromone compositions of Nettle caterpillars differ among species. It was confirmed that several species have an alkyl (7E)-7,9-decadienoate and an alkenyl (7E)-7,9-decadienoate (hereinafter collectively referred to as “(7E)-7,9-decadienoate ester”) as a component in sex pheromone compositions (Non-Patent Literatures 1, 2 and 3).
With regard to a method for producing these sex pheromones of the Nettle caterpillar, there is a report that methyl (7E)-7,9-decadienoate, ethyl (7E)-7,9-decadienoate and butyl (7E)-7,9-decadienoate, which are sex pheromones of Darna pallivitta, can be prepared by a method comprising alkylation of 3-sulfolene, desulfurization, deprotection of THP, oxidation of the alcohol with pyridinium dichromate (PDC) and condensation using N, N′-dicyclohexylcarbodiimide (DCC) (Non-Patent Literature 2). It is also reported that 2-methylbutyl (7E)-7,9-decadienoate and (2E)-2-hexenyl (7E)-7,9-decadienoate, i.e., sex pheromones of Darna trima, and methyl (7E)-7,9-decadienoate and 2-methylpropyl (7E)-7,9-decadienoate, i.e., sex pheromones of Darna bradleyi, can be prepared in a similar method (Non-Patent Literature 3).